Oil Asphaltenes Research Articles

Characteristics of bound biomarkers released from pyrobitumens generated from the cracking of different types of crude oils

Pyrobitumen has attracted significant attention from petroleum geologists and geochemists due to its close relationship with crude oil and natural gas. Generally, the analysis of free biomarkers in pyrobitumen is of limited use, because these biomarkers can be easily modified by biodegradation and thermal alteration. The utilization of bound biomarkers in pyrobitumen appears to be a viable solution to address these issues. However, the compositions and concentrations of bound biomarker moieties in pyrobitumen can also be influenced by external factors such as thermal stress during its formation and the original abundance of asphaltenes in oil. The goal of this study is to examine the evolutionary history of free and bound biomarkers during the formation process of pyrobitumen from different types of crude oil. This is beneficial for the interpretation of covalently bound biomarkers released from natural pyrobitumens in applications such as oil/gas–solid bitumen-source correlation and oil/gas migration studies. Anhydrous and hydrous pyrolysis experiments were conducted on three types of crude oil (condensate, black oil, and heavy oil) to simulate the formation process of pyrobitumen. The comparison of free biomarkers in the liquid residuals of the oil pyrolysis and the bound biomarkers released by the hydropyrolysis of the corresponding pyrobitumen products indicated that the differences between free and bound biomarkers vary with the types of original oils. At elevated thermal maturity (Easy %Ro ≥ ca. 1.0%), the higher the absolute abundance of the asphaltene fraction within a particular oil, the greater the similarity between the distribution of bound biomarkers (especially for steroids) released from pyrobitumen and the corresponding original oil. Thus, the use of pyrobitumen-bound biomarkers formed by heavy oil (asphaltene-rich) can obtain relatively accurate biogenic information on paleo-reservoirs. However, caution should be exercised when employing pyrobitumen-bound biomarkers in paleo-reservoirs formed by light oil (asphaltene-depleted).

Artificial intelligence-based framework for precise prediction of asphaltene particle aggregation kinetics in petroleum recovery

The precipitation and deposition of asphaltene on solid surfaces present a significant challenge throughout all stages of petroleum recovery, from hydrocarbon reservoirs in porous media to wellbore and transfer pipelines. A comprehensive understanding of asphaltene aggregation phenomena is crucial for controlling deposition issues. In addition to experimental studies, accurate prediction of asphaltene aggregation kinetics, which has received less attention in previous research, is essential. This study proposes an artificial intelligence-based framework for precisely predicting asphaltene particle aggregation kinetics. Different techniques were utilized to predict the asphaltene aggregate diameter as a function of pressure, temperature, oil specific gravity, and oil asphaltene content. These methods included the adaptive neuro-fuzzy interference system (ANFIS), radial basis function (RBF) neural network optimized with the Grey Wolf Optimizer (GWO) algorithm, extreme learning machine (ELM), and multi-layer perceptron (MLP) coupled with Bayesian Regularization (BR), Levenberg–Marquardt (LM), and Scaled Conjugate Gradient (SCG) algorithms. The models were constructed using a series of published data. The results indicate the excellent correlation between predicted and experimental values using various models. However, the GWO-RBF modeling strategy demonstrated the highest accuracy among the developed models, with a determination coefficient, average absolute relative deviation percent, and root mean square error (RMSE) of 0.9993, 1.1326%, and 0.0537, respectively, for the total data.

Imidazolium-based ionic liquids as dispersants to improve the stability of asphaltene in Egyptian heavy crude oil

Deposition of asphaltene aggregates can easily depress the oil production, because it may clog the wellbores, annulus, pipelines, and surface facilities. Moreover, asphaltene molecules have a negative effect on the catalytic reactions in the refinery process. Therefore, in this work, three different ionic liquids (IL-H, IL-CH3, and IL-NO2) were synthesized, and characterized using FT-IR and NMR spectroscopy to evaluate their efficiency as asphaltene dispersants. The thermal gravimetric analysis of the prepared ILs showed that IL-H, IL-NO2, and IL-CH3 were thermally stable up to 280 °C. The ILs showed good dispersion activity of the petroleum asphaltenes, where the asphaltene onset precipitation (AOP) was changed from 7.5 to 10.5, 11, and 13.5 ml added n-heptane after the use of IL-H, IL-NO2, and IL-CH3, respectively. Moreover, the colloidal instability index of crude oil was changed from 0.92 (unstable asphaltene) to 0.69 (stable asphaltene). It is noted during the experiments that the presence of an alkyl chain attached to the ionic liquid moiety increases the efficiency of the dispersant. This may be owing to the formation of π–π* with asphaltene molecules due to the presence of electron donating group. Quantum chemical parameters were calculated for the prepared ILs, and the theoretical data confirmed the experimental results.

Pemanfaatan Limbah Gypsum Sebagai Subtitusi Filler Dalam Campuran Aspal Panas Dengan Metode Perendaman Berulang

This research was made using gypsum waste which is expected to improve the quality of asphalt concrete to the characteristics and meet the technical requirements to be used as road pavement materials. This study aims to analyze the characteristics of hot mix asphalt (AC-WC) using oil asphalt with variations of gypsum waste in repeated immersion. This study uses an experimental method, namely an experiment to get results, thus it will be seen the utilization of gypsum waste in asphalt concrete construction with variations in gypsum waste levels of 10%, 15%, and 20%. The results showed that the use of gypsum waste will affect the characteristics of the asphalt mixture

Effect of temperature on the appearance of flocculated asphaltene in an unperturbed unstable American shale oil: Insights from a colloidal modeling

This work aimed to study the onset of flocculation of asphaltenes using optical microscopy and to evaluate the effect of temperature on the destabilization of an unstable undisturbed American shale oil. After magnetic stirring for 24 h, the flocculated asphaltene was redispersed. Increasing the temperature to 40 °C led to asphaltenes flocculating. After heating, the sample was cooled back to room temperature. We calculated the precipitate volume from microscopy data and found that after cooling the system had a larger precipitate volume than in the previously studied scenarios. When comparing the volumes of precipitates before and after cooling, it is possible to observe that the volume of smaller particles does not vary significantly in each class, but the volume of larger particles increases with cooling, indicating an irreversible phenomenon. Statistical analysis of the optical microscopy results allowed a detailed analysis of the phenomenon. To study the colloidal effect, a theoretical analysis was performed based on Hamaker theory and De Gennes scaling theory, presenting compatible results when the parameters of the repulsive term were adjusted. When the parameters of both the attractive term and the repulsive term of the model were kept constant, greater stability was verified with the increase of temperature. Conversely, it was observed that the reduction of the parameter related to the length of the alkyl chains can explain the experimental macroscopic behavior of the shale oil here studied and also some different behaviors reported in the literature, i. e., increasing of flocculated volume with increasing temperature. This size reduction of the length of the alkyl chains can be attributed to a desolvation effect. Hence, the appropriate parameterization of the model showed great potential to mimic the behavior of increasing and also decreasing stability with the increase of temperature. The sets of parameters were related to reaction-limited aggregation (RLA) and diffusion-limited aggregation (DLA), which allowed to interconnect the discussion on experimental stability of asphaltenes, molecular simulation, and the theoretical discussion. Furthermore, the proper use of this theory seems to be a promising way to represent microscopic interactions in asphaltene systems, including previous results from the literature. This work presents (i) an experimental case that shows reversibility of asphaltene flocculation only with magnetic stirring; (ii) the effect of temperature on the stability of asphaltenes, and also (iii) brings a contribution with the volume of precipitate, making it possible to conclude on the irreversibility in the thermal cycle applied. In addition, the proper use of this modeling can predict the stability changes as a function of temperature, being a promising way to represent microscopic interactions in asphaltene systems, including previous results from the literature.

Cold extraction of post-salt oil asphaltenes and their solubilization in deep eutectic solvents

The most used oil deasphalting processes are Residuum Oil Supercritical Extraction Kerr-McGee (ROSE), thermal hydrocracking, and liquid-liquid extraction at lower temperatures from 100° to 150°C. All these processes require a large amount of thermal energy, in which the growing global demand for energy emerges the need to improve more efficient, economical, and environmentally friendly techniques. This work proposes a cold extraction asphaltenes process from oil. In addition to removing asphaltenes, the solubilization of asphaltenes in two Deep Eutectic Solvents (DES) (Thymol:C8 Ac. and Menthol:Thymol) is proposed. These solvents have the advantage of lower toxicity, recyclability, and chemical and thermal stability. The study of the use of these solvents in the oil industry is recent and has shown great potential for its application on a large scale. These asphaltenes were solubilized without saturation up to an initial concentration of 7 g/L, maintaining solubilization for 48 h. These results are a basis for future studies on a pilot scale for industrial application and bioconversion of asphaltenes into value-added products.

UPAYA REHABILITASI EKOSISTEM TERUMBU KARANG TERDAMPAK TUMPAHAN MINYAK DI DESA FAEKHUNA, KECAMATAN AFULU, KABUPATEN NIAS UTARA

Faekhuna'a Village is one of the villages affected by asphalt oil spills. The oil spillage that has polluted the waters has led to a decline in the income of fishermen, due to the damage to coral reefs. To address this problem, direct implementation of the "one house, one coral transplantation" initiative using science and technology (IPTEK) can help mitigate the issues. The objective is to address the problem of asphalt oil spills through the application of IPTEK, optimize the role of the community, educate the community, and create a mindset among the community regarding the importance of environmental factors in the local economy. The method conducted by outreach and simulation. The stages are preparation, participation in the activities by the Faekhuna'a Village officials, 15 members of fisherman group (KUB), PPK 15 students of ORMAWA team and one supervising lecturer, lecturers and students from the University of North Sumatra's Off-Campus Study Program (PSDKU) in North Nias, and support from National Search and Rescue Agency (BASARNAS) of North Nias Regency. Through the program, providing education and awareness about the ecological aspects of life. The application of science and technology (IPTEK) has been warmly received by the community, who have actively contributed to ecosystem restoration through the PPK ORMAWA program. The fishermen has been educated about the crucial role of the coral reef ecosystem in improving the livelihoods. The use of IPTEK, specifically coral transplantation, has proven to be a viable, efficient, complex, adaptable, and compatible approach that is easily implementable.

Analysis of the Spatial Distribution Characteristics of Crude Oils with Different Freezing Points and the Genetic Mechanism of High-Freezing-Point Crude Oils in the Dongying Sag.

The freezing point of crude oils is an important factor affecting the process of exploration, development, and transportation of crude oils. In the Dongying Sag, the freezing point of crude oils varies greatly in space, and high-freezing-point crude oils have been found in many structural belts. The freezing point of crude oils in the Dongying Sag is generally high, ranging from -40 to 80 °C. The distribution of high-freezing-point crude oils in the Dongying Sag is scattered, and they have been found at different depths, layers, and structural belts, with relatively more occurrences in specific areas. Based on the relationship between the wax content and the resin + asphaltene content, the high-freezing-point crude oils in the Dongying Sag can be classified into three types (type A, type B, and type C). Type A, type B, and type C high-freezing-point crude oils are mainly found in the gentle slope zone, depression zone, and uplift zone, respectively. The contents of wax and resins + asphaltenes in crude oils are the key factors controlling the freezing point of crude oils in the Dongying Sag. Oil source correlation using biomarkers and n-alkane carbon isotopes demonstrates that different types of high-freezing-point crude oils are generated from different source rocks, indicating that the source of crude oils is not the only factor controlling the freezing point of crude oils. The hydrocarbon-generating parent material of hydrocarbon source rocks developed in different depositional environments of the Dongying Sag is generally characterized by the dominance of bacteria and algae and is supplemented by terrestrial higher plants. This lays the material foundation for the formation of waxes during the maturation of hydrocarbon source rocks. The change of temperature and pressure conditions during the process of oil expulsion from source rocks and migration in the carrier bed will lead to phase fractionation and composition changes of oils, thus forming type A freezing point crude oils in the slope zone and type B freezing point oils in the depression zone. The increase in resin and asphaltene content caused by biodegradation and water washing in shallower buried oil reservoirs is the reason for the formation of type C high-freezing-point crude oils. The research results indicate that the organic matter composition and hydrocarbon alteration during migration and accumulation jointly control the formation of high-freezing-point crude oils in lacustrine basins. The extensive input of terrestrial organic matter into the source rocks of the lacustrine basin laid the foundation for the formation of high-freezing-point crude oils, and the migration fractionation and biodegradation of the crude oils further promoted the formation of high-freezing-point crude oils.

Inhibiting asphaltenes from agglomeration by controlling the length of aliphatic branches and polarity of anions in imidazolyl ionic liquid polymers

AbstractIonic liquid polymers have been reported being capable of inhibiting the precipitation of asphaltenes, and are expected to further solve problems such as the reduction of oil flowability, reservoir plugging, and blockage of transportation pipeline. In this article, a series of imidazolium‐based ionic liquids containing long aliphatic branches and different anions (Br−, DBSA−, and DEHP−) were synthesized by free radical polymerization and to explore the influence of polymers on asphaltenes, model oil containing Tahe asphaltenes was prepared. The initial precipitation point (IPP), particle size of asphaltenes in model oil were measured, and morphology of asphaltene precipitates was observed by microscope. The rheological behaviors of Tahe crude oil in the presence ionic liquid polymers were examined by analyzing the viscosity–temperature curves. The results show that among all the synthesized ionic liquid polymers, the [IM16E18] [DBSA] can increase the IPP from 36% to 69%, reduce the size of asphaltene precipitates by 76.3%, and decrease the viscosity of crude oil by 64.9% at the dosage of 0.5%. The ionic liquid polymers can inhibit asphaltene precipitation at a low concentration of 50 ppm, which are one of promising inhibitors for heavy crude oil containing asphaltenes.

Investigation on blending characteristics in asphalt mixtures with recycled asphalt and waste cooking oil as rejuvenator

ABSTRACT Reclaimed asphalt pavement (RAP) mixtures reduces environmental burden by utilising existing pavement material. However, RAP percent is limited due to performance issues at higher RAP content due to improper blending. The degree of blending can be improved using rejuvenator. Waste cooking oil (WCO) is gaining attention as a potential rejuvenator in recycled mixtures. However, past studies have shown contradictory results on WCO influence in asphalt mixture and have not investigated the influence of WCO on blending. This study is devised with a methodological approach to investigate the influence of WCO on blending in asphalt mixtures. Four blending approaches were formulated with four RAP and WCO contents resulting in a total of 148 mixture combinations. The blending characteristics were evaluated by assessing the workability and moisture damage resistance. The optimum mixtures were determined by Grey relational analysis, which were further investigated. The results showed the WCO doses determined from blending equation resulted in the higher dose than optimum WCO. The mixtures with medium dose and dry mixing of WCO showed the highest resistance to moisture damage. Further, for utilising higher than 30% RAP, higher binder content is required as compared to conventional mixture to increase the functional binder in the mixture.

Distribution characteristics of Sulfur, phosphorus and trace elements in crude oil and source rock chloroform asphaltenes “a” and description of an oil-bearing system in the Ordos Basin

The multiple sets of source rocks and crude oil biomarkers in the Yanchang Formation have no clear results of oil-source correlation. Chloroform asphaltenes “A” was extracted from the source rocks and crude oils and microwave digested, and its elemental composition analyzed by ICP–MS for oil-source correlation. The S/P and the ratio of light and heavy rare earth elements are oil-source correlation indices. The total amount of transition metals may be useful for oil-oil and oil-source correlation using cluster analysis techniques, but redox parameters are not effective for oil-oil and oil-source correlation in lacustrine oil. It is proposed that the oils in the Longdong area and Jiyuan area all come from the Chang 7 source rocks. The oils in the Shanbei area are derived from the Chang 9 source rocks in the area and the Chang 7 source rocks in Longdong. The Chang 10 oils in the Shanbei area and Chang 9 oils in the middle Lake Basin appear to come from other sources. Trace elements can provide valuable clue on the hydrocarbon sources and oil migration patterns of the Yanchang Formation, which is of great significance in the search for possible deep oil-bearing systems in the Shanbei area.

Experimental study on nanoparticles-assisted low-salinity water for enhanced oil recovery in asphaltenic oil reservoirs

The purpose of this research is to look into the augmentation of silica nanoparticles (NPs) with low salinity (LowSal) brine for EOR. A series of analyses, including oil/water interfacial tension (IFT) and rock wettability tests were undertaken to determine an optimal dispersion to flood into a porous carbonate core with a defined pore size distribution. At 60 °C and 14.5 psi, the maximum drop (i.e., roughly 12.5 mN/m) in oil/water IFT by 0.3 wt.% brine occurred, but when 0.08 wt.% silica was added to the brine, the IFT reduced to 14.51 mN/m at 60 °C and 14.5 psi. The wettability analysis revealed a significant reduction in contact angle, from 142° to 72° and 59°, using 0.04 and 0.08 wt.% silica in LowSal brine, but the extent reduced by brine alone was insufficient. The results of rock pore size characterization were discussed in terms of the accomplishment of operating EOR in the porous medium in the presence of NPs. The addition of 0.08 wt. % silica to the injected brine resulted in an additional oil recovery of 16.3% OOIP as well as a significant shift in the endpoints/cross-points of the oil/water relative permeability curves. The findings of this research might help improve oil recovery from asphaltenic oil reservoirs or, more environmentally friendly, remediate petroleum crude-oil polluted soil.

Assessment of asphaltene and resin fractions in crude oil using laser-induced fluorescence spectroscopy based on modified Beer-Lambert (LIFS-MBL)

Crude oil is one of the most significant petrogenic sources of polycyclic aromatic compounds (PACs). These substances play an essential role in the pollution of the marine environment. Therefore, the rapid identification of this pollutant source and its fractions is vital. For this purpose, a fast and on-site method of laser-induced fluorescence spectroscopy based on modified Beer-Lambert (LIFS-MBL) is proposed here using solvent densitometry. Three optical parameters of the self-quenching (K), the extinction (α), and the peak concentration (Cp) are experimentally extracted from MBL graphs. Note that the parameters above are known to be unique characteristics of various crude oils. The corresponding compounds are generally classified into saturate, aromatic, resin, and asphaltene fractions, abbreviated as SARA. Differentiation among these fractions is achieved using the LIFS-MBL method by selecting the optimal excitation wavelength at 405 nm. This line effectively rules out the light aromatic rings and focuses on heavy fractions. The correlation of optical parameters with heavy oil fractions is verified according to analysis of variance. Statistical relations are proposed to calculate crude oil fractions values. The values of light fractions including saturate and aromatic components can also be determined by the heavy fractions. In this method, the test time is notably reduced from four days using the standard methods to less than half an hour according to the presented LIFS-MBL technique.

Karakteristik Aspal Buton Ekstraksi yang Dimodifikasi dengan Oli Bekas dan Plastik HDPE

Asphalt functions as an aggregate binder in the road pavement mixture. The rapid construction of roads causes the need for asphalt to increase, while its availability is limited. The government is promoting the use of natural asphalt (Asbuton) as an alternative to oil asphalt. However, asphalt performance from Asbuton is not good. Uneven asphalt content and Asbuton hardness are factors causing it to be less effective as a binder. It is necessary to improve performance by modifying the bitumen separated from Asbuton granules by the extraction process. The modifications were made using used oil and high-density polyethylene (HDPE) plastic waste. Samples were made for each variation of used oil and HDPE in two ways: a constant 5% used oil composition and a constant 2% HDPE. In the constant 5% oil variation, 0%, 2%, 4%, and 6% HDPE are used. Whereas at a constant 2% HDPE, 0%, 3%, 5%, and 7% used oil are used. The tests carried out were: 1) Moisture content and ash content of asphalt extracted from Asbuton, 2) Penetration of asphalt, 3) Ductility; 4) Loss of weight, 5) specific gravity, 6) softening point, and 7) flash and burn points. The performance of modified asphalt is known from the results of data analysis from the tests carried out. The results of the analysis showed that in the asphalt weight loss test, specific gravity, and softening point, pure Asbuton extraction asphalt and the results of the modification as a whole met the requirements. However, in the penetration test, only 3 variations met the requirements, namely: 5% and 7% used oil, and 2% and 6% HDPE. Whereas in the ductility test, flash point, and burning point, all variations and asphalt extraction of pure Asbuton did not meet the requirements. Low ductility, meaning that asphalt does not have good cohesive properties. The low flash point and burning point indicate that the asphalt is easy and fast to burn, which affects the mixing process. Thus, it is still necessary to optimize the composition of the modifier so that the requirements for ductility, flash point, and firing point are met.

Rheological Properties and Microscopic Morphology Evaluation of UHMWPE-Modified Corn Stover Oil Bio-Asphalt

In order to promote the efficient utilization of bio-oil, corn stover oil and petroleum asphalt were used to prepare bio-asphalt. UHMWPE was adopted to strengthen the high-temperature properties of bio-asphalt. UHMWPE-modified corn stover oil asphalt was prepared. Rheological and microscopic tests were carried out to study its performance. The softening point and viscosity of the modified asphalt were enhanced with a rise in the UHMWPE dosage. Its ductility and deformation ability increased at 5 °C. An MSCR test suggested that the asphalt’s creep recovery ability and anti-rutting properties decreased at a high stress level. Meanwhile, the low-temperature rheological behavior of UHMWPE-modified corn stover oil asphalt was superior to that of neat asphalt. The corn stover oil ameliorated the asphalt’s low-temperature properties but weakened its high-temperature behavior. The optimal preparation schemes for UHMWPE-modified corn stover oil asphalt were recommended through a comprehensive analysis of the properties. The recommended dosage of UHMWPE was 3–4%, while the corn stover oil dosage was 5%. However, when the dosage of corn stover oil was 10%, the recommended dosage of UHMWPE was 4%. UHMWPE powder was melted and cross-linked with neat asphalt during high-temperature preparation, demonstrating that UHMWPE can enhance the properties of asphalt. The UHMWPE polymer macromolecules can be dispersed in corn stover oil. UHMWPE can form a compact and robust network structure with asphalt. The feasible application of corn stover oil in road engineering was verified, which provides efficient solutions for waste utilization. This study will contribute to the sustainable development of road construction.

Role of Reservoir Brine and Rock in Modulating Asphaltene Stability: Insights from Experimental Analysis

Summary The stability of asphaltenes in crude oil is influenced by various factors, including interactions with reservoir components such as brine and rock formations. While previous research has focused on pressure and temperature effects, a comprehensive understanding of the combined impact of brine and reservoir rock on asphaltene stability is lacking. This study investigates the individual and combined influences of brine and rock formations on asphaltene stability. First, 11 crude oil samples from diverse locations were characterized using API gravity, viscosity, and saturates, aromatics, resins, and asphaltenes (SARA) fraction analysis. The elemental composition of the crude oils, including carbon, hydrogen, nitrogen, and various metals, was determined. The surface properties of asphaltenes were analyzed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The interaction between asphaltenes and deionized water was examined through zeta potential, particle size, conductivity, and pH measurements. The behavior of asphaltenes in an 8,000 ppm NaCl solution was also investigated. The SEM analysis revealed the presence of inorganic content on the surfaces of asphaltenes, indicating interactions between asphaltenes and reservoir rock. A strong correlation between the zeta potential and sulfur content of asphaltenes was observed, highlighting the influence of sulfur compounds on surface charge and stability in heavy crudes. Additionally, the correlation between total dissolved solids (TDS) content and alkaline Earth metals and alkali metals in asphaltenes confirmed interactions between asphaltenes and reservoir brine. This interaction is likely influenced by the composition and properties of both the brine and reservoir rock. The presence of electrical charges on the asphaltene surfaces, as determined by zeta potential measurements, further supports the role of electrostatic interactions in asphaltene stability. The low precipitation tendency observed for most asphaltene samples, coupled with the abundance of negatively charged particles, underscores the importance of electrical charges in controlling stability. This study provides novel insights into asphaltene stability, highlighting the significance of surface charge and elemental composition. The results demonstrate the substantial impact of both reservoir brine and rock formations on asphaltene stability in crude oil. Further research is needed to unravel the complex mechanisms underlying these interactions and their implications in diverse reservoir environments.

Characterization of the micromorphology of asphalt surfaces using atomic force microscopy

The surface micromorphology (SMM) of asphalt considerably affects its macroperformance. Herein, the SMM of seven types of asphalt was observed using atomic force microscopy. Moreover, the roughness theory was employed to quantitatively analyze and evaluate the surface roughness of the asphalt. The influences of the oil source, grade, styrene–butadiene–styrene (SBS) modification, aging, and water immersion of asphalt on the SMM of five types of matrix asphalt and two types of modified asphalt were elucidated. Results show that the surface roughness of KL-90 asphalt is considerably higher than those of KL-70 and KL-110 asphalts for the same oil sources. The surface roughness of SMM varies with variations in the asphalt oil source, and the surface roughness of ZH-90 asphalt is greater than that of SK-90 asphalt. After SBS modification, the SMM of the asphalt becomes smooth. The surface roughness of the asphalt first gradually increases and then rapidly decreases with aging. After the water immersion of the asphalt, its SMM roughens under the action of “water–asphalt” interfacial tension.

Experimental Evaluation of Kinetic Behavior of Asphaltene Particles: Effect of Temperature, Shear Stress, and Inhibitors

Summary Asphaltene deposits under a variety of temperatures and shear stresses in reservoirs, wells, and crude oil transmission pipelines, and it is currently one of the most serious problems in the oil industry. The size of asphaltene particles strongly affects the deposition rate. The particle size is mainly determined by aggregation rate that depends on shear rate and temperature. Therefore, different shear rates of 127 s–1 and 254 s−1 were applied within Couette flow at 25°C, 45°C, and 65°C, and the particle size was analyzed by using an optical microscope. Crude oil viscosity and asphaltene solubility were determined using a capillary tube viscometer and IP143 procedure, respectively. In this work, the effects of four additives, namely, dodecyl benzene sulfonic acid (DBSA), nonyl phenol (NP), salicylic acid (SA), and benzoic acid (BA), were studied on the aggregation of asphaltene particles in a light crude oil. The additives were chosen based on their functional groups. Moreover, asphaltene functional groups were determined using a Fourier transform infrared (FTIR) analyzer to better understand the behavior of inhibitors in preventing the aggregation of asphaltene particles at different conditions. DBSA, BA, and SA were inhibitors, and NP behaved as a promoter. According to the results, the presence of acidic groups, SO3H in DBSA and COOH in SA and BA, increases the interaction of inhibitor with asphaltene and so reduces the aggregation of asphaltene particles. The stronger acidic group of DBSA improved its performance compared to other inhibitors. Both increasing temperature and increasing shear stress resulted in higher collisions of asphaltene particles and thus lowered the efficiency of inhibitors at a constant concentration.

Variation and mechanism of asphalt-aggregate interface features under ultraviolet aging based on meso- and micro-observations

Time-dependent variation and mechanism of asphalt-aggregate interface features under ultraviolet (UV) aging have not yet been illustrated. This study explored the time-dependent variation and mechanism of asphalt-aggregate interface features under UV aging. To this end, six asphalt binders were chosen and subjected to different durations of UV aging, and then the variation behaviors of their cohesion-adhesion ability with the changing UV radiation time were analyzed through surface energy theory. Further, the microscopic attributes of asphalt binders experiencing the various UV aging durations were measured and their varying rules were investigated with a series of micro observations. Finally, the relationship between cohesion-adhesion characteristics and microscopic properties were illustrated and thus the variation mechanism of interfacial cohesion and adhesion were revealed by mathematical statistics and image presentation. The results showed that UV aging weakened the cohesion and multi-working adhesion of asphalt binders and the moisture stability of asphalt-aggregate systems, and overall presented a gradually strengthened influence on them with the prolonged UV radiation time, especially the UV radiation exceeded 6 days. The variation of phase morphology of asphalt binders under UV aging depended on the asphalt types and neat asphalt oil sources, and there existed a favorable linear relationship between Catana phase of asphalt binders and surface roughness. Adhesion force, function group and four components (saturate (S), aromatics (Ar), resin (R) and asphaltene (As)) also exhibited a gradually increasing variation as the UV radiation duration went on, and among which, the UV aging reduced the adhesion force of asphalt binders. Adhesion force Fad demonstrated the highest Pearson relevance with the cohesion and aqueous-condition adhesion and the moisture stability of asphalt-aggregate system, and the cohesion-adhesion properties of asphalt binders under UV aging met the multivariate linear mathematical relationship with the microscopic attributes screened, with the goodness-of-fit greater than 0.7000.

The emulsions stabilized by Dodecylbenzenesulfonic acid/asphaltene/hydrolyzed polyacrylamide: Emulsion morphology, stability, and rheology

Aqueous mixtures of dodecylbenzene sulfonic acid (DBSA) and hydrolyzed polyacrylamide (HPAM) are commonly used to enhance oilfield recovery. These two components coupled with asphaltenes (ASP) in crude oil, play a key role in stabilizing the emulsions produced during oil recovery. In this study, the stability of emulsions made with ASP, DBSA, and HPAM as emulsifiers was examined. We discovered that the three ingredients were synergistically adsorbed at the oil–water interface with a synergistic index of 1.075 for interfacial tension (IFT). HPAM enhanced the viscosity and increased the anion content of the dispersed system in the emulsion. DBSA acted as the main anionic surfactant, benefiting to form and stabilize the emulsion droplets. ASP was adsorbed at the oil–water interface to form a rigid interfacial film. When the three ingredients co-existed, they formed a complex adsorption unit with synergistic adsorption, in which DBSA dominated. As the concentration of the three ingredients increased, the emulsion stability showed a trend of enhancing first and then decreasing. This study is dedicated to providing a theoretical basis for the elucidation of the stability of the oil–water system in oil sludge containing polymers.